TWI784131B - Phase shift mask substrate, manufacturing method of phase shift mask, and manufacturing method of display device - Google Patents

Abstract

The invention provides a phase shifting mask substrate with high transmittance, which can pattern the phase shifting film into a cross-sectional shape that can fully exert the phase shifting effect. The phase shift mask substrate of the present invention is characterized in that it has a phase shift film on a transparent substrate and has an etched mask film on the phase shift film, and the above phase shift mask substrate is a matrix The master plate is used to form the phase shift film on the above-mentioned transparent substrate by wet etching the above-mentioned phase shift film by using the etching mask film pattern that forms the above-mentioned etching mask film into a desired pattern as a mask. The phase shift mask of the shift film pattern, the above phase shift film contains transition metal, silicon, and oxygen, the content of oxygen is not less than 510 atomic % and not more than 70 atomic %, throughout the above interface to a region with a depth of 10 nm, The content ratio of oxygen to silicon is 3.0 or less.

Description

Phase shift mask substrate, manufacturing method of phase shift mask, and manufacturing method of display device

The present invention relates to a phase-shift mask substrate, a method for manufacturing a phase-shift mask using it, and a method for manufacturing a display device.

In recent years, in display devices such as FPD (Flat Panel Display) represented by LCD (Liquid Crystal Display), along with larger screen size and wider viewing angle, high-definition, high-speed display is also high-speed. develop. One of the elements necessary for this high-definition and high-speed display is to produce circuit patterns such as elements and wirings with fine and high dimensional accuracy. The patterning of the circuit for the display device mostly uses photolithography. Therefore, there is a need for a phase shift mask for display device manufacture in which a fine and high-precision pattern is formed.

For example, in Patent Document 1, a base mask for flat panel display and a mask using the same are disclosed. The base mask for flat panel display is used for wet etching a thin film containing molybdenum silicide in order to make the transparent substrate To minimize damage, the film containing molybdenum silicide was wet etched with an etching solution prepared by diluting phosphoric acid, hydrogen peroxide, and ammonium fluoride with water. Also, in Patent Document 2, a phase inversion base mask and a photomask are disclosed. The phase inversion base mask is for the purpose of improving the precision of patterns, and the phase inversion film 104 includes a layer that can be etched by the same etching solution. Films with different compositions are formed in the form of a multilayer film or a continuous film of at least two or more layers formed by laminating each film of a different composition one or more times. [Prior Art Literature] [Patent Document]

[Patent Document 1] Korean Patent Application Publication No. 10-2016-0024204 [Patent Document 2] Japanese Patent Laid-Open No. 2017-167512

[Problem to be solved by the invention]

In recent years, as a phase shift mask substrate for the manufacture of such display devices, in order to reliably transfer fine patterns less than 2.0 μm, a phase shift film with a transmittance of 10% or more relative to the exposed light has been studied. , Furthermore, as a phase shift film having an optical characteristic of 20% or more, a phase shift film containing oxygen at a certain ratio (5 atomic % or more, further 10 atomic % or more) is used. However, in the case of patterning such a phase shift film having an oxygen content of 5 atomic % or more, and further 10 atomic % or more, by wet etching, it has been found that the wet etching solution penetrates into the phase shift. The interface between the film and the etching mask film formed thereon, the etching of the interface part will proceed faster. The cross-sectional shape of the edge portion of the formed phase shift film pattern has a gradient, and becomes a tapered shape with a hem.

In the case where the cross-sectional shape of the edge portion of the phase shift film pattern is a tapered shape, as the film thickness of the edge portion of the phase shift film pattern decreases, the phase shift effect becomes smaller. Therefore, the phase shift effect cannot be fully exhibited, and a fine pattern of less than 2.0 μm cannot be stably transferred. If the content of oxygen in the phase shift film is set to 5 atomic % or more, and further 10 atomic % or more, it is difficult to strictly control the cross-sectional shape of the edge part of the phase shift film pattern, and it is very difficult to control the line width (CD) .

Therefore, the present invention was made in view of the above-mentioned problems, and its object is to provide a phase shifting film with a high transmittance that can be patterned into a cross-sectional shape that can fully exert the phase shifting effect by wet etching. A manufacturing method of a photomask substrate, a phase shifting mask having a phase shifting film pattern capable of fully exerting a phase shifting effect, and a manufacturing method of a display device using the phase shifting mask. [Technical means to solve the problem]

In order to solve these problems, the inventors of the present invention intensively studied a method of verticalizing the cross-sectional shape of the edge portion of the phase shift film pattern. Experiments and discussions were carried out on the state of the interface between the phase shift film and the etching mask film containing transition metals, silicon, and oxygen. An important reason for the infiltration of oxide systems. Furthermore, the present inventors conducted further research and found that the composition gradient region formed at the interface with the phase shift film includes a region where the ratio of oxygen increases stepwise and/or continuously toward the depth direction, and throughout the above-mentioned phase When the phase shift film and the etching mask film are formed so that the content ratio of oxygen to silicon is 3.0 or less in the region from the interface between the offset film and the above-mentioned etching mask film to a depth of 10 nm, the transition metal existing at the interface can be suppressed Oxide, which can inhibit the infiltration at the interface. The present invention has been accomplished through intensive studies as above, and has the following constitutions.

(Constitution 1) A phase shift mask base, characterized in that: it has a phase shift film on a transparent substrate, and has an etching mask film on the phase shift film, and The above-mentioned phase shift mask base is a master for performing wet processing on the above-mentioned phase-shift film by using an etching mask film pattern in which a desired pattern is formed on the above-mentioned etching mask film as a mask. Etching and forming a phase shift mask with a phase shift film pattern on the above transparent substrate, The above-mentioned phase shift film contains a transition metal, silicon, and oxygen, and the content of oxygen is not less than 5 atomic % and not more than 70 atomic %, A composition gradient region is formed at the interface between the phase shift film and the etching mask film, and the composition gradient region includes a region where the oxygen ratio increases stepwise and/or continuously toward the depth direction, The content ratio of oxygen to silicon is 3.0 or less throughout the interface between the phase shift film and the etching mask film to a depth of 10 nm.

(Structure 2) The phase shift mask substrate according to the structure 1, wherein the phase shift film includes a plurality of layers.

(Structure 3) The phase shift mask substrate according to the structure 1, wherein the phase shift film includes a single layer.

(Structure 4) The phase shift mask base according to any one of the structures 1 to 3, wherein the phase shift film contains nitrogen.

(Structure 5) The phase shift mask substrate according to any one of structures 1 to 4, wherein the content of nitrogen in the phase shift film is 2 atomic % or more and 60 atomic % or less.

(Structure 6) The phase shift mask substrate according to any one of the structures 1 to 5, wherein the film stress of the phase shift film is not less than 0.2 GPa and not more than 0.8 GPa.

(Structure 7) The phase shift mask substrate according to any one of the structures 1 to 6, wherein the etching mask film is made of a chromium-based material.

(Structure 8) The phase shift mask substrate according to any one of structures 1 to 7, wherein the etching mask film contains at least one of nitrogen, oxygen, and carbon.

(Structure 9) The phase-shift mask substrate according to any one of structures 1 to 8, wherein the above-mentioned transparent substrate is a rectangular substrate, and the length of the short side of the transparent substrate is 300 mm or more.

(Structure 10) A method for manufacturing a phase shift mask, characterized by comprising the following steps: preparing a phase shift mask substrate as described in any one of the structures 1 to 9; forming a resist film on the above-mentioned phase shift mask substrate; A resist film pattern is formed by drawing a desired pattern on the resist film and developing it, and using the resist film pattern as a mask, the etching mask film is patterned by wet etching to form The above-mentioned etched mask pattern; and A phase shift film pattern is formed on the transparent substrate by performing wet etching on the phase shift film by using the etching mask film pattern as a mask.

(Structure 11) A method of manufacturing a display device, characterized by comprising the following steps: using a phase shift mask manufactured using a phase shift mask substrate as described in any one of Structures 1 to 9, or using a phase shift mask manufactured by using a method such as The manufacturing method of the phase shift mask described in 10 constitutes the manufactured phase shift mask, and transfers the transfer pattern exposure to the resist film on the display device. [Effect of Invention]

According to the phase shift mask substrate of the present invention, the phase shift film can be patterned into a cross-sectional shape that can fully exert the phase shift effect by wet etching, and the phase shift mask substrate with high transmittance can be obtained. In addition, it is possible to obtain a phase shift mask substrate in which the phase shift film can be patterned into a cross-sectional shape with a small CD deviation by wet etching.

Also, according to the method of manufacturing a phase shift mask of the present invention, the phase shift mask can be manufactured using the above phase shift mask substrate. Therefore, it is possible to manufacture a phase shift mask having a phase shift film pattern that can fully exert the phase shift effect. Also, a phase shift mask having a phase shift film pattern with a small CD deviation can be manufactured. The phase shift mask can cope with the miniaturization of line and space patterns or contact holes.

In addition, according to the manufacturing method of the display device of the present invention, it is possible to use the phase shift mask manufactured by using the above phase shift mask substrate, or the phase shift mask obtained by the above phase shift mask manufacturing method display device. Therefore, a display device having fine line and space patterns or contact holes can be manufactured.

Implementation form 1. In Embodiment 1, a phase shift mask base will be described. The phase shift mask base is a master for wet etching a phase shift film by using an etching mask film pattern in which a desired pattern is formed on the etching mask film as a mask. A phase shift mask with a phase shift film pattern formed on a transparent substrate.

FIG. 1 is a schematic diagram showing the film constitution of a phase shift mask substrate 10 . The phase shift mask base 10 shown in FIG. 1 includes a transparent substrate 20 , a phase shift film 30 formed on the transparent substrate 20 , and an etching mask film 40 formed on the phase shift film 30 .

The transparent substrate 20 is transparent to exposure light. When the transparent substrate 20 is set to have no surface reflection loss, it has a transmittance of 85% or more, preferably 90% or more, with respect to the exposed light. The transparent substrate 20 includes materials containing silicon and oxygen, and may include glass materials such as synthetic quartz glass, quartz glass, aluminosilicate glass, soda lime glass, and low thermal expansion glass (SiO ₂ -TiO ₂ glass, etc.). In the case where the transparent substrate 20 includes low thermal expansion glass, the position change of the phase shift film pattern caused by the thermal deformation of the transparent substrate 20 can be suppressed. Moreover, the transparent substrate 20 for phase shift mask bases used for a display device is normally a rectangular substrate, and the length of the short side of this transparent substrate is 300 mm or more. The present invention can provide stable transfer of the phase shift of the fine phase shift film pattern formed on the transparent substrate, for example, less than 2.0 μm, even if the length of the short side of the transparent substrate is large in size of 300 mm or more Phase-shift the mask base for the mask.

The phase shift film 30 includes transition metal silicide-based materials containing transition metals, silicon, and oxygen. As the transition metal, molybdenum (Mo), tantalum (Ta), tungsten (W), titanium (Ti), zirconium (Zr) and the like are preferable. In addition, the phase shift film 30 may contain nitrogen. When nitrogen is contained, the refractive index is increased, so it is preferable in terms of reducing the thickness of the film used to obtain a retardation. Also, if the content of nitrogen contained in the phase shift film 30 is increased, the absorption coefficient of the complex refractive index becomes large, and high transmittance cannot be realized. The content of nitrogen contained in the phase shift film 30 is preferably not less than 2 atomic % and not more than 60 atomic %. More preferably, it is not less than 2 atomic % and not more than 50 atomic %, and still more preferably not less than 5 atomic % and not more than 30 atomic %. Examples of transition metal silicide-based materials include oxides of transition metal silicides, oxynitrides of transition metal silicides, oxycarbides of transition metal silicides, and oxycarbonitrides of transition metal silicides. Also, in terms of easily obtaining an excellent pattern cross-sectional shape by wet etching, the transition metal silicide-based materials are preferably molybdenum silicide-based materials (MoSi-based materials), zirconium silicide-based materials (ZrSi-based materials), silicide-based materials, etc. Molybdenum-zirconium-based materials (MoZrSi-based materials). The phase shift film 30 has the function of adjusting the reflectance of light incident from the side of the transparent substrate 20 (hereinafter sometimes referred to as the back reflectance), and the function of adjusting the transmittance and phase difference of the exposed light. The phase shift film 30 can be formed by sputtering.

The transmittance of the phase shift film 30 with respect to the exposed light satisfies the value required as the phase shift film 30 . The transmittance of the phase shift film 30 is preferably 10% to 70%, more preferably 15% to 65%, and more preferably Preferably it is 20% to 60%. That is, when the light to be exposed is composite light including light in a wavelength range of 313 nm to 436 nm, the phase shift film 30 has the above-mentioned transmittance with respect to light of a representative wavelength included in the wavelength range. For example, when the light to be exposed is composite light including i-rays, h-rays, and g-rays, the phase shift film 30 has the above-mentioned transmittance with respect to any one of i-rays, h-rays, and g-rays. The transmittance of the phase shift film 30 can be adjusted by the atomic ratio of the transition metal and silicon contained in the phase shift film 30 . In order to make the transmittance of the phase shift film 30 the above transmittance, the atomic ratio of the transition metal to silicon is configured to be 1:1 or more and 1:15 or less. In order to improve the chemical resistance (cleaning resistance) of the phase shift film 30, the atomic ratio of the transition metal to silicon is preferably not less than 1:2 and not more than 1:15, and more preferably not less than 1:4 and not more than 1:10. The following is more ideal. The transmittance can be measured using a phase shift measurement device or the like.

The phase difference of the phase shift film 30 with respect to the exposed light satisfies the value required for the phase shift film 30 . The phase difference of the phase shift film 30 is preferably 160° to 200°, more preferably 170° to 190°, with respect to the light of the representative wavelength included in the exposed light. With this property, the phase of the light of the representative wavelength included in the exposure light can be changed to 160°-200°. Therefore, a phase difference of 160° to 200° is generated between the light of the representative wavelength transmitted through the phase shift film 30 and the light of the representative wavelength transmitted only through the transparent substrate 20 . That is, when the light to be exposed is composite light including light in a wavelength range of 313 nm to 436 nm, the phase shift film 30 has the above-mentioned phase difference for light of a representative wavelength included in the wavelength range. For example, when the light to be exposed is composite light including i-rays, h-rays, and g-rays, the phase shift film 30 has the aforementioned phase difference with respect to any one of i-rays, h-rays, and g-rays. The phase difference can be measured using a phase shift measurement device or the like.

The back reflectance of the phase shift film 30 is less than 15%, preferably less than 10% in the wavelength range of 365 nm to 436 nm. Also, when the exposed light includes j-rays, the back reflectance of the phase shift film 30 is preferably 20% or less, more preferably 17% or less, with respect to light in the wavelength region of 313 nm to 436 nm. Furthermore, it is more preferably 15% or less. In addition, the back reflectance of the phase shift film 30 is 0.2% or more in the wavelength region of 365 nm to 436 nm, preferably 0.2% or more with respect to light in the wavelength region of 313 nm to 436 nm. The back reflectance can be measured using a spectrophotometer or the like.

The content of oxygen contained in the phase shift film 30 is adjusted so that the phase shift film 30 has the above-mentioned retardation and transmittance, and optionally so that the phase shift film 30 has the above-mentioned rear reflectance. Specifically, the phase shift film 30 is configured such that the content of oxygen is not less than 5 atomic % and not more than 70 atomic %. The content of oxygen contained in the phase shift film 30 is preferably not less than 10 atomic % and not more than 70 atomic %. The phase shift film 30 may include multiple layers or a single layer. The phase shift film 30 including a single layer is preferable in that it is difficult to form an interface in the phase shift film 30 and it is easy to control the cross-sectional shape. On the other hand, the phase shift film 30 including a plurality of layers is preferable in terms of easiness of film formation and the like. Also, the light elements of nitrogen and oxygen contained in the phase shift film 30 may be uniformly contained in the film thickness direction of the phase shift film 30, or may be increased or decreased stepwise or continuously. In addition, it is preferable that the content of nitrogen and the content of oxygen mentioned above become the above-mentioned specific content in the region of 50% or more of the film thickness of the phase shift film 30 . In addition, the phase shift film 30 of the phase shift mask substrate 10 is required to have high chemical resistance (cleaning resistance). In order to improve the chemical resistance (cleaning resistance) of the phase shift film 30, it is effective to increase the film density. The film density of the phase shift film 30 is related to the film stress. In consideration of chemical resistance (cleaning resistance), the film stress of the phase shift film 30 is preferably higher. On the other hand, with regard to the film stress of the phase shift film 30, it is necessary to consider the dislocation when forming the phase shift film pattern and the loss of the phase shift film pattern. From the above point of view, the film stress of the phase shift film 30 is preferably not less than 0.2 GPa and not more than 0.8 GPa, and more preferably not less than 0.4 GPa and not more than 0.8 GPa.

The etching mask film 40 is disposed on the upper side of the phase shift film 30 and includes a material having etching resistance to an etching solution for etching the phase shift film 30 . In addition, the etching mask film 40 may not only have the function of blocking the transmission of the exposed light, but also may have the function of making the phase shift film 30 relative to the light incident from the side of the phase shift film 30. Reduce the reflectance of the film surface so that the reflectance of the film surface becomes 15% or less in the wavelength range of 350 nm to 436 nm. The etching mask film 40 contains, for example, a chrome-based material. More specifically, the chromium-based material includes chromium (Cr), or a material containing at least any one of chromium (Cr) and oxygen (O), nitrogen (N), and carbon (C). Alternatively, a material containing chromium (Cr), at least any one of oxygen (O), nitrogen (N), and carbon (C), and further containing fluorine (F) may be used. For example, as a material constituting the etching mask film 40, Cr, CrO, CrN, CrF, CrCO, CrCN, CrON, CrCON, and CrCONF are exemplified. The etching mask film 40 can be formed by sputtering.

When the etching mask film 40 has the function of blocking the transmission of the exposed light, the optical density of the layered part of the phase shift film 30 and the etching mask film 40 relative to the exposed light is preferably 3 or more, More preferably, it is 3.5 or more, Still more preferably, it is 4 or more. The optical density can be measured using a spectrophotometer, an OD (Optical Density, optical density) meter, or the like.

Depending on the function, the etching mask film 40 may include a single-layer film with a uniform composition, multiple layers with different compositions, or a single-layer film with a composition continuously changing in the thickness direction.

Furthermore, the phase shift mask substrate 10 shown in FIG. The present invention can also be applied to a phase-shift photomask substrate with a resist film on the film 40 .

In addition, the phase shift mask substrate 10 is formed with a composition gradient region at the interface between the phase shift film 30 and the etching mask film 40, and the ratio of oxygen contained in the composition gradient region is stepped and/or Constructed in a manner of continuously increasing regions. More specifically, in the above-mentioned composition gradient region, at least in the depth direction from the interface of the phase shift film 30 and the etching mask film 40 toward the transparent substrate 20 side, there is a ratio of oxygen stepwise and/or continuously increased area. Furthermore, the phase shift mask base 10 is formed so that the content ratio of oxygen to silicon is 3.0 or less throughout the interface between the phase shift film 30 and the etching mask film 40 to a depth of 10 nm. The interface is set at such a position that when the composition analysis of the phase shift mask substrate 10 is performed by X-ray photoelectron spectroscopy, the ratio of the transition metal decreases from the phase shift film 30 toward the etching mask film 40 and the ratio of the transition metal The position where the content becomes 0 atomic % for the first time. Throughout the interface between the phase shift film 30 and the etching mask film 40 to a region with a depth of 10 nm, the content ratio of oxygen to silicon is required to be 3.0 or less, preferably 2.8 or less, further preferably 2.5 or less, and still more preferably Below 2.0 is ideal. Furthermore, from the viewpoint of film quality continuity between the phase shift film 30 and the composition gradient region, the content ratio of oxygen to silicon is preferably 0.3 or more, more preferably 0.5 or more.

Next, a method of manufacturing the phase shift mask substrate 10 of this embodiment will be described. The phase shift mask substrate 10 shown in FIG. 1 is manufactured by performing the following phase shift film forming step and etching mask film forming step. Hereinafter, each step will be described in detail.

1. Phase Shift Film Formation Step First, a transparent substrate 20 is prepared. The transparent substrate 20 may be any glass material including synthetic quartz glass, quartz glass, aluminosilicate glass, soda lime glass, low thermal expansion glass (SiO ₂ -TiO ₂ glass, etc.), as long as it is transparent to the exposed light. By.

Next, a phase shift film 30 is formed on the transparent substrate 20 by sputtering. The phase shift film 30 is formed by sputtering palladium containing a transition metal and silicon as main components of the material constituting the phase shift film 30, or sputtering palladium containing a transition metal, silicon, oxygen, and/or nitrogen, For example, in a sputtering gas environment containing at least one inert gas selected from the group consisting of helium, neon, argon, krypton and xenon, or in a sputtering gas environment containing the above inert gas and a gas selected from oxygen and carbon dioxide , nitrogen monoxide gas, and nitrogen dioxide gas in a sputtering gas atmosphere of a mixed gas of at least one active gas.

The composition and thickness of the phase shift film 30 are adjusted so that the phase shift film 30 has the aforementioned retardation and transmittance. The composition of the phase shift film 30 can be controlled by the content ratio of elements constituting sputtered palladium (for example, the ratio of transition metal content to silicon content), the composition and flow rate of sputtering gas, and the like. The thickness of the phase shift film 30 can be controlled by sputtering power, sputtering time and so on. Moreover, when the sputtering apparatus is an in-line type sputtering apparatus, the thickness of the phase shift film 30 can also be controlled by the conveyance speed of a board|substrate. In this manner, the oxygen content of the phase shift film 30 is controlled so as to be 5 atomic % or more and 70 atomic % or less.

When the phase shift films 30 each include a single-layer film with a uniform composition, the above-mentioned film-forming process is performed only once without changing the composition and flow rate of the sputtering gas. In the case where the phase shift film 30 includes a plurality of films with different compositions, the above-mentioned film forming process is performed a plurality of times while changing the composition and flow rate of the sputtering gas for each film forming process. The phase shift film 30 can also be formed into a film using the target which differs in the content ratio of the element which comprises sputtering palladium. When the phase shift film 30 includes a single-layer film whose composition continuously changes in the thickness direction, the above-mentioned film-forming process is performed only once by changing the composition and flow rate of the sputtering gas as the film-forming process elapses. In the case of performing a plurality of film-forming processes, the sputtering power applied to the palladium sputtering can be reduced.

2. Surface treatment steps After forming the phase shift film 30 comprising a transition metal silicide material containing transition metal, silicon, and oxygen, the surface of the phase shift film 30 is easily oxidized, and oxides of transition metals are easily formed. In order to suppress the penetration of the etchant due to the presence of transition metal oxides, a surface treatment step is performed to adjust the state of oxidation of the surface of the phase shift film 30 . As a surface treatment step for adjusting the surface oxidation state of the phase shift film 30, a method of surface treatment with an acidic aqueous solution, a method of surface treatment with an alkaline aqueous solution, and a surface treatment with dry treatment such as ashing method etc. As long as a composition gradient region is formed at the interface between the phase shift film 30 and the etching mask film 40 after the etching mask film forming step described below, the ratio of oxygen contained in the composition gradient region is stepwise and/or continuous toward the depth direction. Furthermore, any surface treatment step can be performed if the content ratio of oxygen to silicon is 3.0 or less throughout the interface between the phase shift film 30 and the etching mask film 40 to a depth of 10 nm. For example, in the method of surface treatment with an acidic aqueous solution and the method of surface treatment with an alkaline aqueous solution, the surface of the phase shift film 30 can be adjusted by appropriately adjusting the concentration, temperature, and time of the acidic or alkaline aqueous solution. state of oxidation. The method of surface treatment with an acidic aqueous solution and the method of surface treatment with an alkaline aqueous solution include immersing a substrate having a phase shift film 30 formed on a transparent substrate 20 in the aforementioned aqueous solution. method, and the method of bringing the above-mentioned aqueous solution into contact with the phase shift film 30, and the like. 3. Etching mask film formation step After performing surface treatment to adjust the surface oxidation state of the surface of the phase shift film 30, an etching mask film 40 is formed on the phase shift film 30 by sputtering. In this way, a phase shift mask substrate 10 is obtained.

The film-forming system of etching mask film 40 uses sputtering palladium comprising chromium or chromium compounds (chromium oxide, chromium nitride, chromium carbide, chromium oxynitride, chromium oxycarbonitride, etc.), A sputtering gas environment containing at least one inert gas selected from the group consisting of helium, neon, argon, krypton and xenon A mixture of at least one inert gas and a mixed gas containing at least one active gas selected from the group consisting of oxygen, nitrogen, nitrogen monoxide gas, nitrogen dioxide gas, carbon dioxide gas, hydrocarbon gas, and fluorine gas in a sputtering gas environment. As hydrocarbon-based gas, methane gas, butane gas, propane gas, styrene gas, etc. are mentioned, for example.

When the etching mask film 40 includes a single-layer film with a uniform composition, the above-mentioned film-forming process is performed only once without changing the composition and flow rate of the sputtering gas. In the case where the etching mask film 40 includes a plurality of films with different compositions, the above-mentioned film forming process is performed a plurality of times by changing the composition and the flow rate of the sputtering gas for each film forming process. When the etching mask film 40 consists of a single-layer film whose composition continuously changes in the thickness direction, the above-mentioned film-forming process is performed only once by changing the composition and flow rate of the sputtering gas as the film-forming process elapses.

In this way, by carrying out the film-forming process of the phase shift film 30 and the etching mask film 40, and the surface treatment for adjusting the surface oxidation state of the surface of the phase shift film 30, it is possible to achieve a positive effect on the phase shift film 30 and the etching mask film 40. The interface of the film 40 forms a composition gradient region, which includes a region where the ratio of oxygen increases stepwise and/or continuously toward the depth direction, and extends over the interface between the phase shift film and the above-mentioned etching mask film to a depth of 10 The phase shift film 30 and the etching mask film 40 are formed so that the content ratio of oxygen to silicon is 3.0 or less in the region of nm.

Furthermore, the surface treatment for adjusting the surface oxidation state of the phase shift film 30 has been described, but in the film formation process of the phase shift film 30, it may be changed so that it is difficult to make the phase shift in the second half of the film formation process. The gas species that undergoes surface oxidation on the surface of the transfer film 30, or the above-mentioned gas species, etc., thereby including the area where the ratio of oxygen in the above-mentioned composition gradient area increases stepwise and/or continuously toward the depth direction, and throughout the phase shift From the interface between the film and the etching mask film to a depth of 10 nm, the content ratio of oxygen to silicon was 3.0 or less.

Furthermore, the phase shift mask substrate 10 shown in FIG. 1 has an etching mask film 40 on the phase shift film 30 , so when manufacturing the phase shift mask substrate 10 , an etching mask film forming step is performed. Also, when manufacturing a phase shift mask base having an etching mask film 40 on the phase shift film 30 and a resist film on the etching mask film 40, after the etching mask film forming step, the etching A resist film is formed on the mask film 40 .

The phase shift mask substrate 10 of the first embodiment is to form a composition gradient region at the interface between the phase shift film 30 and the etching mask film 40, and the ratio of oxygen contained in the composition gradient region is gradually and/or toward the depth direction. or a continuously increasing region, and the phase shift film 30 and the etching mask are formed in such a way that the content ratio of oxygen to silicon is 3.0 or less throughout the interface between the phase shift film and the above-mentioned etching mask film to a depth of 10 nm. Film 40. Thereby, it is possible to effectively inhibit the etchant from penetrating into the interface between the phase shift film 30 and the etching mask film 40, which can help the verticalization of the pattern cross section, and can obtain a phase shift film pattern formed with excellent CD uniformity. The phase offset mask. Also, in the case where the etched mask pattern remains on the phase shift film pattern in the phase shift mask, it is possible to suppress reflection from the mask pellicle attached to the phase shift mask or the display device substrate. influences. In addition, the phase-shift mask substrate 10 of the first embodiment can form a phase-shift film pattern with good cross-sectional shape, small CD deviation, and high transmittance by wet etching. Therefore, a phase shift mask substrate capable of manufacturing a phase shift mask capable of transferring a high-definition phase shift film pattern with high precision can be obtained.

Implementation form 2. In Embodiment 2, the manufacturing method of a phase shift mask is demonstrated.

FIG. 2 is a schematic diagram showing a method of manufacturing a phase shift mask. The manufacturing method of the phase-shifted mask shown in FIG. 2 is a method of manufacturing a phase-shifted mask using the phase-shifted mask substrate 10 shown in FIG. 1, comprising the following steps: on the following phase-shifted mask substrate 10 A resist film is formed on the resist film; a resist film pattern 50 is formed by drawing a desired pattern on the resist film and developing it (the first resist film pattern forming step); the resist film pattern 50 is formed As a mask, the etching mask film 40 is patterned by wet etching to form an etching mask film pattern 40a (first etching mask film pattern forming step); by using the etching mask film pattern 40a as a mask , perform wet etching on the phase shift film 30, and form the phase shift film pattern 30a on the transparent substrate 20 (phase shift film pattern forming step). And it further includes the 2nd resist film pattern formation process, and the 2nd etching mask film pattern formation process. Hereinafter, each step will be described in detail.

1. The first resist film pattern formation step In the first resist film pattern forming step, first, a resist film is formed on the etching mask film 40 of the phase shift mask base 10 according to the first embodiment. The resist film material used is not particularly limited. For example, it may be sensitive to laser light having any wavelength selected from the wavelength range of 350 nm to 436 nm described below. In addition, the resist film may be either a positive type or a negative type. Thereafter, a desired pattern is drawn on the resist film using laser light having any wavelength selected from the wavelength region of 350 nm to 436 nm. The pattern drawn on the resist film is a pattern to be formed on the phase shift film 30 . As a pattern drawn on a resist film, a line and space pattern or a hole pattern is mentioned. Thereafter, the resist film is developed with a specific developer, and as shown in FIG. 2( a ), a first resist film pattern 50 is formed on the etching mask film 40 .

2. The first etching mask film pattern forming step In the first etching mask pattern forming step, first, the etching mask film 40 is etched using the first resist film pattern 50 as a mask to form the first etching mask pattern 40a. The etching mask film 40 is formed of a chromium-based material including chromium (Cr). The etchant for etching the etching mask film 40 is not particularly limited as long as it can selectively etch the etching mask film 40 . Specifically, an etching solution containing ceric ammonium nitrate and perchloric acid is mentioned. Thereafter, the first resist film pattern 50 is peeled off as shown in FIG. 2( b ) using a resist stripping solution or by ashing. If necessary, the next step of forming the phase shift film pattern may be performed without peeling off the first resist film pattern 50 .

3. Phase shift film pattern formation step In the step of forming the first phase shift film pattern, the phase shift film 30 is etched using the first etching mask film pattern 40a as a mask to form the phase shift film pattern 30a as shown in FIG. 2( c ). As the phase shift film pattern 30a, a line and space pattern or a hole pattern can be mentioned. The etchant for etching the phase shift film 30 is not particularly limited as long as it can selectively etch the phase shift film 30 . For example, an etching solution containing ammonium fluoride, phosphoric acid, and hydrogen peroxide, and an etching solution containing ammonium hydrogen fluoride and hydrogen chloride are mentioned.

4. Second resist film pattern forming step In the second resist film pattern forming step, first, a resist film covering the first etching mask film pattern 40a is formed. The resist film material used is not particularly limited. For example, it may be sensitive to laser light having any wavelength selected from the wavelength range of 350 nm to 436 nm described below. In addition, the resist film may be either a positive type or a negative type. Thereafter, a desired pattern is drawn on the resist film using laser light having any wavelength selected from the wavelength region of 350 nm to 436 nm. The pattern drawn on the resist film is a light-shielding belt pattern that shields the peripheral region of the patterned region of the phase shift film 30 and a light-shielding belt pattern that shields the central portion of the phase shift film pattern. In addition, the pattern drawn on the resist film may be a pattern without the light-shielding band pattern which shields the central part of the phase shift film pattern 30a depending on the transmittance of the phase shift film 30 with respect to the exposed light. Thereafter, the resist film is developed with a specific developer, and as shown in FIG. 2( d ), a second resist film pattern 60 is formed on the first etching mask film pattern 40 a.

5. The second etching mask film pattern forming step In the second etching mask film pattern forming step, the first etching mask film pattern 40a is etched with the second resist film pattern 60 as a mask, as shown in FIG. 2( e), a second etching mask is formed. Mask pattern 40b. The first etching mask pattern 40a is formed of a chromium-based material including chromium (Cr). The etchant for etching the first etching mask pattern 40a is not particularly limited as long as it can selectively etch the first etching mask pattern 40a. For example, an etchant containing ammonium cerium nitrate and perchloric acid is mentioned. Thereafter, the second resist film pattern 60 is peeled off using a resist stripping solution or by ashing. In this way, the phase shift mask 100 is obtained. Furthermore, in the above description, the case where the etching mask film 40 has the function of blocking the transmission of exposed light has been described, but the etching mask film 40 only has a hardness when etching the phase shift film 30. In the case of the function of the mask, in the above description, the second resist film patterning step and the second etching mask film patterning step are not performed, and the first etching masking step is performed after the phase shift film patterning step. The mask film pattern is peeled off, so that the phase shift mask 100 is produced.

According to the manufacturing method of the phase shift mask of the second embodiment, since the phase shift mask base of the first embodiment is used, a phase shift film pattern with a good cross-sectional shape and a small CD deviation can be formed. Therefore, it is possible to manufacture a phase shift mask capable of accurately transferring a high-definition phase shift film pattern. A phase shift mask fabricated in this way can cope with the miniaturization of line and space patterns or contact holes.

Implementation form 3. In Embodiment 3, a method of manufacturing a display device will be described. The display device is performed by performing the steps of using the phase shift mask 100 manufactured using the above phase shift mask substrate 10 or using the phase shift mask 100 manufactured by the above method of manufacturing the phase shift mask 100 (a photomask placing step) and a step (pattern transfer step) of exposing and transferring the transferred pattern to the resist film on the display device. Hereinafter, each step will be described in detail.

1. Loading steps In the mounting step, the phase shift mask manufactured in Embodiment 2 is mounted on the mask stage of the exposure device. Here, the phase shift mask is disposed so that the projection optical system of the exposure device faces the resist film formed on the display device substrate.

2. Pattern transfer step In the pattern transfer step, the phase shift mask 100 is irradiated with exposure light to transfer the phase shift film pattern to the resist film formed on the display device substrate. The light for exposure is composite light including light of multiple wavelengths selected from the wavelength region of 365 nm to 436 nm, or monochromatic light selected by cutting off a certain wavelength region from the wavelength region of 365 nm to 436 nm by means of filters, etc. Light. For example, the exposure light is composite light including i-rays, h-rays, and g-rays, or monochromatic light of i-rays. If the composite light is used as the light for exposure, the intensity of the light for exposure can be increased and the productivity can be increased, thus reducing the manufacturing cost of the display device.

According to the method for manufacturing a display device according to the third embodiment, it is possible to manufacture a high-definition display device with high resolution, fine line and space patterns, or contact holes, which can suppress CD errors. [Example]

Example 1. A. Phase Shift Mask Substrate and Manufacturing Method In order to manufacture the phase shift mask base of Example 1, first, as the transparent substrate 20, a synthetic quartz glass substrate having a size of 1214 (1220 mm×1400 mm) was prepared.

Thereafter, the synthetic quartz glass substrate was mounted on a tray (not shown) with the main surface facing downward, and carried into the chamber of the in-line sputtering apparatus. In order to form the phase shift film 30 on the main surface of the transparent substrate 20, first, argon (Ar) gas, carbon dioxide gas (CO ₂ ), nitrogen (N ₂ ) Gas mixture (Ar: 20 sccm, CO ₂ : 10 sccm, N ₂ : 20 sccm), apply 6.0 kW sputtering to the first palladium sputtering (molybdenum: silicon = 1: 4) containing molybdenum and silicon Plating power is to deposit molybdenum silicide carbonitride containing molybdenum, silicon, oxygen, nitrogen and carbon on the main surface of the transparent substrate 20 by reactive sputtering. Then, a phase shift film 30 having a film thickness of 202 nm was formed. Moreover, after the phase shift film 30 is formed on the transparent substrate 20, it is taken out from the chamber, and the surface of the phase shift film 30 is treated with an alkaline aqueous solution. In addition, the surface treatment conditions were set at an alkali concentration of 0.7%, a temperature of 30 degrees, and a surface treatment time of 1200 seconds.

Next, the transparent substrate 20 with the phase shift film 30 after the surface treatment is carried into the second chamber, and argon (Ar) gas and nitrogen (N ₂ ) are introduced into the second chamber under a state of a certain vacuum degree. Gas mixture (Ar: 65 sccm, N ₂ : 15 sccm). Then, a sputtering power of 1.5 kW is applied to the second sputtering palladium containing chromium, and chromium nitride (CrN) (film thickness 15 nm) containing chromium and nitrogen is formed on the phase shift film 30 by reactive sputtering. ). Next, in the state where the third chamber is set to a certain degree of vacuum, a mixed gas (30 sccm) of argon (Ar) gas and methane (CH ₄ : 4.9%) gas is introduced, and palladium is sputtered on the third chamber containing chromium. A sputtering power of 8.5 kW was applied to form chromium carbide (CrC) containing chromium and carbon (film thickness 60 nm) on CrN by reactive sputtering. Finally, a mixed gas of argon (Ar) gas and methane (CH ₄ : 5.5%) gas, nitrogen (N ₂ ) gas, and oxygen (O ₂ ) gas are introduced in the fourth chamber with a certain vacuum degree. Gas mixture (Ar+CH ₄ : 30 sccm, N ₂ : 8 sccm, O ₂ : 3 sccm), applying a sputtering power of 2.0 kW to the fourth sputtering palladium containing chromium, by reactive sputtering on CrC Formation of chromium carbonitride (CrCON) containing chromium, carbon, oxygen and nitrogen (film thickness 30 nm). As above, the etching mask film 40 of the laminated structure of the CrN layer, the CrC layer, and the CrCON layer is formed on the phase shift film 30 . In this way, the phase shift mask base 10 with the phase shift film 30 and the etching mask film 40 formed on the transparent substrate 20 is obtained.

For the obtained phase shift film 30 of the phase shift mask substrate 10 (the phase shift film 30 in which the surface of the phase shift film 30 has been surface-treated with an aqueous alkali solution), MPM-100 manufactured by Lasertec Co., Ltd. , to measure the transmittance and phase difference. The transmittance and phase difference of the phase shift film 30 were measured using a substrate with a phase shift film 30 formed on the main surface of a synthetic quartz glass substrate (dummy substrate) that was placed on the same tray. ). The transmittance and phase difference of the phase shift film 30 were measured by taking out the substrate (dummy substrate) with the phase shift film from the chamber before forming the etching mask film 40 . As a result, the transmittance was 22.1% (wavelength: 365 nm), and the phase difference was 161 degrees (wavelength: 365 nm). Furthermore, the film thickness of the phase shift film 30 subjected to the surface treatment with the alkaline aqueous solution was 183 nm, which was reduced from the film thickness immediately after film formation. Also, for the phase shift film 30, the change in flatness was measured using UltraFLAT 200M (manufactured by Corning Tropel Co., Ltd.), and the film stress was calculated to be 0.46 GPa. The change in transmittance and phase difference of the phase shift film 30 to the chemical solution (sulfuric acid hydrogen peroxide mixture, ammonia water hydrogen peroxide mixture, ozone water) used for cleaning the phase shift mask is small, It has high chemical resistance and washing resistance.

Moreover, the reflectance and optical density of the film surface were measured with the spectrophotometer SolidSpec-3700 manufactured by Shimadzu Corporation about the obtained phase shift mask base. The film surface reflectance of the phase shift mask substrate (etching mask film 40) is 8.3% (wavelength: 436 nm), and the optical density OD is 4.0 (wavelength: 436 nm). It can be seen that this etching mask film functions as a light-shielding film whose reflectance on the film surface is low.

Furthermore, the obtained phase shift mask substrate 10 was subjected to compositional analysis in the depth direction by X-ray photoelectron spectroscopy (XPS). FIG. 3 shows the composition analysis results in the depth direction obtained by XPS for the phase shift mask substrate of Example 1. FIG. FIG. 3 shows the composition analysis results of the etching mask film 40 and the phase shift film 30 on the side of the phase shift film 30 in the phase shift mask substrate. 3 represents the depth (nm) in terms of SiO ₂ of the phase shift mask substrate 10 based on the outermost surface of the etching mask film 40, and the vertical axis represents the content (atomic %). In FIG. 3 , each curve represents changes in the content of silicon (Si), nitrogen (N), oxygen (O), carbon (C), chromium (Cr), and molybdenum (Mo).

As shown in FIG. 3 , in the composition analysis results in the depth direction obtained by XPS for the phase shift mask substrate 10, the interface between the phase shift film 30 and the etching mask film 40 (the ratio of the transition metal from the phase shift The transfer film 30 decreases toward the etching mask film 40, and the transition metal content becomes 0 atomic % for the first time), and the ratio of chromium decreases from the etching mask film 40 toward the phase shift film 30, and the chromium content becomes 0 atomic % for the first time. The region up to the position of 0 atomic % is the composition gradient region, and the ratio of oxygen generated by the phase shift film 30 monotonously increases stepwise and/or continuously toward the depth direction. 7 is a graph showing the O/Si ratio (the content ratio of oxygen to silicon) in the depth direction obtained by XPS for the phase shift mask substrates of Example 1 and Comparative Example 1. As shown in FIG. 7 , in the phase shift mask substrate of Example 1, the maximum value of the content ratio of oxygen to silicon is 2.0, below 3.0. This interface is set at a position where the ratio of the transition metal (molybdenum in this case) is from the phase shifted mask substrate 10 when the composition analysis of the phase shift mask substrate 10 is performed by X-ray photoelectron spectroscopy from the etching mask film 40 side. The offset film 30 decreases toward the etching mask film 40, and the transition metal content becomes 0 atomic % for the first time.

The chromium (Cr) generated by etching the mask film 40 disappears until the peak of oxygen (O) generated by the transparent substrate 20 appears (before the molybdenum (Mo) generated by the phase shift film 30 decreases sharply). In the homogeneous composition area, the content of molybdenum (Mo) is 12 atomic % on average, the content of silicon (Si) is 23 atomic % on average, the content of nitrogen (N) is 13 atomic % on average, and the content of oxygen (O) The content rate of carbon (C) is 40 atomic % on average, the content rate of carbon (C) is 12 atomic % on average, and the variation of each content rate is 3 atomic % or less.

B. Phase shift mask and manufacturing method thereof In order to manufacture the phase shift mask 100 using the phase shift mask substrate 10 manufactured in the above manner, first, a photoresist is coated on the etching mask film 40 of the phase shift mask substrate 10 using a resist coating device. resist film. Thereafter, a photoresist film having a film thickness of 520 nm was formed through heating and cooling steps. Thereafter, the photoresist film was drawn using a laser drawing device, and after developing and rinsing steps, a line and space pattern with a width of 1.8 μm and a width of 1.8 μm was formed on the etching mask film. The resist film pattern.

Thereafter, using the resist film pattern as a mask, the etching mask film is wet-etched with a chromium etchant containing ammonium cerium nitrate and perchloric acid to form a first etching mask film pattern 40a.

Thereafter, using the first etching mask film pattern 40a as a mask, the phase shift film 30 is wet-etched using a molybdenum silicide etching solution prepared by diluting a mixed solution of ammonium bifluoride and hydrogen peroxide with pure water, A phase shift film pattern 30a is formed. Thereafter, the resist film pattern is peeled off.

Thereafter, a photoresist film is applied so as to cover the first etching mask film pattern 40 a using a resist coating device. Thereafter, a photoresist film having a film thickness of 520 nm was formed through heating and cooling steps. Thereafter, the photoresist film is drawn using a laser drawing device, and after developing and rinsing steps, a second resist film pattern 60 for forming a light-shielding band is formed on the first etching mask film pattern 40a.

Thereafter, using the second resist film pattern 60 as a mask, the first etching mask film pattern 40a formed in the transfer pattern forming region is wetted with a chromium etchant containing cerium ammonium nitrate and perchloric acid. type etching. Thereafter, the second resist film pattern 60 is peeled off.

In this way, the phase shift of the phase shift film pattern 30a formed in the transfer pattern forming region and the light-shielding band including the layered structure of the phase shift film pattern 30a and the etching mask film pattern 40b formed on the transparent substrate 20 is obtained. Reticle 100.

The cross section of the obtained phase shift mask was observed with a scanning electron microscope. In Example 1 and Comparative Example 1 below, a scanning electron microscope was used to observe the cross section of the phase shift mask. FIG. 4 is a cross-sectional photo of the phase shift mask of Example 1. FIG.

As shown in FIG. 4 , the phase shift film pattern formed on the phase shift mask of Example 1 has a nearly vertical cross-sectional shape that can fully exert the phase shift effect. Also, in the phase shift film pattern, no penetration was observed at any of the interface with the etching mask film pattern and the interface with the substrate. Also, it has a phase shift film pattern with a small hem width and a small CD variation. In detail, the cross section of the phase shift film pattern includes the upper surface, the lower surface and the side surface of the phase shift film pattern. In the cross section of the phase shift film pattern, the angle formed by the part where the upper surface meets the side (upper side) and the part where the side and the lower surface meet (lower side) is 53 degrees. Therefore, an excellent phase shift effect is obtained for exposure light including light in the wavelength range of 300 nm to 500 nm, more specifically, composite light including i-rays, h-rays, and g-rays Phase shift mask. Moreover, in the cross-section of the phase shift film pattern of Example 1, the angle formed by the part (upper side) where the upper surface meets the side surface and the part (lower side) where the side surface meets the lower surface is 53 degrees, exceeding the angle that can be obtained by The lower limit of cross-section control for over-etching is 45 degrees. Therefore, when forming the phase shift film pattern of Example 1, the cross-sectional shape can be further verticalized by performing over-etching.

The CD deviation of the phase shift film pattern of the phase shift mask was measured by SIR8000 manufactured by Seiko Instruments NanoTechnology. The measurement of CD deviation is measured at 11×11 points in an area of 1100 mm×1300 mm except the peripheral region of the substrate. CD deviation is compared to the offset width of the target line and space pattern (width of line pattern: 1.8 μm, width of space pattern: 1.8 μm). In Example 1 and Comparative Example 1, the same device was used for the measurement of CD deviation. CD deviation was good at 0.096 μm. Therefore, it can be said that when the phase shift mask of Example 1 is set on the mask stage of the exposure device and exposed to the resist film transferred on the display device, it can be transferred with high precision up to 2.0 μm of fine patterns.

Example 2. A. Phase Shift Mask Substrate and Manufacturing Method In order to manufacture the phase shift mask base of Example 2, as in Example 1, a synthetic quartz glass substrate having a size of 1214 (1220 mm×1400 mm) was prepared as the transparent substrate 20 .

In order to form the phase shift film 30 on the main surface of the transparent substrate 20, first, argon (Ar) gas, helium (He ) gas, nitrogen (N ₂ ) gas mixture (Ar: 18 sccm, He: 50 sccm, N ₂ : 13 sccm), on the first sputtering palladium containing molybdenum and silicon (molybdenum: silicon = 1:9) A sputtering power of 7.6 kW was applied, and molybdenum silicide oxynitride containing molybdenum, silicon, oxygen, and nitrogen was deposited on the main surface of the transparent substrate 20 by reactive sputtering. Then, a phase shift film 30 having a film thickness of 150 nm was formed.

Next, after forming the phase shift film 30 on the transparent substrate 20, no surface treatment is performed, and an etching mask of a laminated structure of a CrN layer, a CrC layer, and a CrCON layer is formed on the phase shift film 30 in the same manner as in Example 1. Film 40. In this way, the phase shift mask base 10 with the phase shift film 30 and the etching mask film 40 formed on the transparent substrate 20 is obtained.

The transmittance and phase difference were measured with MPM-100 manufactured by Lasertec Corporation about the obtained phase shift film of a phase shift mask base. The transmittance and phase difference of the phase shift film were measured using a substrate (dummy substrate) with a phase shift film 30 formed on the main surface of a synthetic quartz glass substrate that was placed on the same tray. . The transmittance and phase difference of the phase shift film were measured by taking out the substrate (dummy substrate) with the phase shift film from the chamber before forming the etching mask film. As a result, the transmittance was 27.0% (wavelength: 405 nm), and the phase difference was 178 degrees (wavelength: 405 nm). Also, for the phase shift film, the change in flatness was measured using UltraFLAT 200M (manufactured by Corning Tropel Co., Ltd.), and the film stress was calculated to be 0.21 GPa. The change in transmittance and phase difference of the phase shift film 30 to the chemical solution (sulfuric acid hydrogen peroxide mixture, ammonia water hydrogen peroxide mixture, ozone water) used for cleaning the phase shift mask is small, It has high chemical resistance and washing resistance.

Moreover, the reflectance and optical density of the film surface were measured with the spectrophotometer SolidSpec-3700 manufactured by Shimadzu Corporation about the obtained phase shift mask base. The film surface reflectance of the phase shift mask substrate (etching mask film 40) is 8.3% (wavelength: 436 nm), and the optical density OD is 4.0 (wavelength: 436 nm). It can be seen that this etching mask film functions as a light-shielding film whose reflectance on the film surface is low.

Furthermore, the obtained phase shift mask substrate 10 was subjected to compositional analysis in the depth direction by X-ray photoelectron spectroscopy (XPS). FIG. 8 shows the composition analysis results in the depth direction obtained by XPS for the phase shift mask substrate of Example 2. FIG. FIG. 8 shows the composition analysis results of the etching mask film 40 and the phase shift film 30 on the side of the phase shift film 30 in the phase shift mask substrate. The horizontal axis of FIG. 8 represents the depth (nm) in terms of SiO ₂ of the phase shift mask substrate 10 based on the outermost surface of the etching mask film 40, and the vertical axis represents the content (atomic %). In FIG. 8 , each curve represents changes in the content of silicon (Si), nitrogen (N), oxygen (O), carbon (C), chromium (Cr), and molybdenum (Mo).

As shown in FIG. 8 , in the composition analysis results of the phase shift mask substrate 10 obtained by XPS in the depth direction, the interface between the phase shift film 30 and the etching mask film 40 (the ratio of the transition metal from the phase shift The transfer film 30 decreases toward the etching mask film 40, and the transition metal content becomes 0 atomic % for the first time), and the ratio of chromium decreases from the etching mask film 40 toward the phase shift film 30, and the chromium content becomes 0 atomic % for the first time. The region up to the position of 0 atomic % is the composition gradient region, and the ratio of oxygen increases toward the depth direction and then decreases from the interface between the phase shift film 30 and the etching mask film 40 . 10 is a graph showing the O/Si ratio (the content ratio of oxygen to silicon) in the depth direction obtained by XPS for the phase shift mask substrates of Example 2 and Example 3. As shown in FIG. 10 , the maximum value of the content ratio of oxygen to silicon is 2.0, which is 3.0 or less, from the interface between the phase shift film 30 and the etching mask film 40 to a depth of 10 nm.

The chromium (Cr) generated by etching the mask film 40 disappears until the peak of oxygen (O) generated by the transparent substrate 20 appears (before the molybdenum (Mo) generated by the phase shift film 30 decreases sharply). In the homogeneous composition area, the content of molybdenum (Mo) is 8 atomic % on average, the content of silicon (Si) is 40 atomic % on average, the content of nitrogen (N) is 46 atomic % on average, and the content of oxygen (O) The rate is 6 atomic % on average. In the phase shift film 30, the change in the content of molybdenum (Mo) is the smallest, which is less than 2 atomic %. Next, the change in the content of silicon (Si) is less than 3 atomic %, and the content of nitrogen (N) is less than 3 atomic %. The fluctuation is 4 atomic % or less, and the fluctuation of the content rate of oxygen (O) is 5 atomic % or less.

B. Phase shift mask and manufacturing method thereof Using the phase shift mask substrate manufactured in the above manner, a phase shift mask was manufactured by the same method as in Example 1. The cross section of the obtained phase shift mask was observed with a scanning electron microscope. FIG. 9 is a cross-sectional photograph of the phase shift mask of Example 2. FIG.

As shown in FIG. 9 , the phase shift film pattern formed on the phase shift mask of Example 2 has a nearly vertical cross-sectional shape that can fully exert the phase shift effect. Also, in the phase shift film pattern, no penetration was observed at any of the interface with the etching mask film pattern and the interface with the substrate. Also, it has a phase shift film pattern with a small hem width and a small CD variation. In detail, the cross section of the phase shift film pattern includes the upper surface, the lower surface and the side surface of the phase shift film pattern. In the cross-section of the phase shift film pattern, the angle formed by the part where the upper surface meets the side surface (upper side) and the part where the side surface meets the lower surface (lower side) is 74 degrees. Therefore, an excellent phase shift effect is obtained for exposure light including light in the wavelength range of 300 nm to 500 nm, more specifically, composite light including i-rays, h-rays, and g-rays Phase shift mask. Also, CD variation was good at 0.092 μm. Moreover, in the cross-section of the phase shift film pattern of Example 2, the angle formed by the part (upper side) where the upper surface meets the side surface and the part (lower side) where the side surface meets the lower surface is 74 degrees, exceeding the angle that can be obtained by The lower limit of cross-section control for over-etching is 45 degrees. Therefore, when forming the phase shift film pattern of Example 2, the cross-sectional shape can be further verticalized by performing over-etching. Therefore, it can be said that when the phase shift mask of Example 2 is set on the mask stage of the exposure device and exposed to the resist film transferred on the display device, it can be transferred with high precision up to 2.0 μm of fine patterns.

Embodiment 3. A. Phase-shift mask substrate and its manufacturing method In order to manufacture the phase-shift mask substrate of Embodiment 3, as in Embodiment 1, prepare a 1214 size (1220 mm×1400 mm) as the transparent substrate 20 ) of synthetic quartz glass substrates. In order to form the phase shift film 30 on the main surface of the transparent substrate 20, first, argon (Ar) gas, helium (He ) gas, nitrogen (N ₂ ) gas, and nitrogen monoxide gas (NO) gas mixture (Ar: 18 sccm, He: 50 sccm, N ₂ : 13 sccm, NO: 4 sccm), for molybdenum and silicon The first palladium sputtering (molybdenum:silicon=1:9) applied a sputtering power of 7.6 kW, and deposited molybdenum silicide containing molybdenum, silicon, oxygen, and nitrogen on the main surface of the transparent substrate 20 by reactive sputtering of nitrogen oxides. Then, a phase shift film 30 having a film thickness of 140 nm was formed. Then, after the phase shift film 30 was formed on the transparent substrate 20, it was taken out from the chamber, and under the same conditions as in Example 1, the surface of the phase shift film 30 was treated with an alkaline aqueous solution. .

Next, in the same manner as in Example 1, an etching mask film 40 of a laminated structure of a CrN layer, a CrC layer, and a CrCON layer was formed on the phase shift film 30 . In this way, the phase shift mask base 10 with the phase shift film 30 and the etching mask film 40 formed on the transparent substrate 20 is obtained.

The transmittance and phase difference were measured with MPM-100 manufactured by Lasertec Corporation about the obtained phase shift film of a phase shift mask base. The transmittance and phase difference of the phase shift film were measured using a substrate (dummy substrate) with a phase shift film 30 formed on the main surface of a synthetic quartz glass substrate that was placed on the same tray. . The transmittance and phase difference of the phase shift film were measured by taking out the substrate (dummy substrate) with the phase shift film from the chamber before forming the etching mask film. As a result, the transmittance was 33.0% (wavelength: 365 nm), and the phase difference was 169 degrees (wavelength: 365 nm). Also, for the phase shift film, the change in flatness was measured using UltraFLAT 200M (manufactured by Corning Tropel Co., Ltd.), and the film stress was calculated to be 0.26 GPa. The change in transmittance and phase difference of the phase shift film 30 to the chemical solution (sulfuric acid hydrogen peroxide mixture, ammonia water hydrogen peroxide mixture, ozone water) used for cleaning the phase shift mask is small, It has high chemical resistance and washing resistance.

Moreover, the reflectance and optical density of the film surface were measured with the spectrophotometer SolidSpec-3700 manufactured by Shimadzu Corporation about the obtained phase shift mask base. The film surface reflectance of the phase shift mask substrate (etching mask film 40) is 8.3% (wavelength: 436 nm), and the optical density OD is 4.0 (wavelength: 436 nm). It can be seen that this etching mask film functions as a light-shielding film whose reflectance on the film surface is low. Furthermore, the obtained phase shift mask substrate 10 was subjected to compositional analysis in the depth direction by X-ray photoelectron spectroscopy (XPS). FIG. 11 shows the composition analysis results in the depth direction obtained by XPS for the phase shift mask substrate of Example 3. FIG. FIG. 11 shows the composition analysis results of the etching mask film 40 and the phase shift film 30 on the side of the phase shift film 30 in the phase shift mask substrate. 11 represents the depth (nm) in terms of SiO ₂ of the phase shift mask substrate 10 based on the outermost surface of the etching mask film 40 , and the vertical axis represents the content (atomic %). In FIG. 8 , each curve represents changes in the content of silicon (Si), nitrogen (N), oxygen (O), carbon (C), chromium (Cr), and molybdenum (Mo).

As shown in FIG. 11 , in the composition analysis results in the depth direction obtained by XPS for the phase shift mask substrate 10, the interface between the phase shift film 30 and the etching mask film 40 (the ratio of the transition metal from the phase shift The transfer film 30 decreases toward the etching mask film 40, and the transition metal content becomes 0 atomic % for the first time), and the ratio of chromium decreases from the etching mask film 40 toward the phase shift film 30, and the chromium content becomes 0 atomic % for the first time. The region up to the position of 0 atomic % is the composition gradient region, and the ratio of oxygen increases toward the depth direction and then decreases from the interface between the phase shift film 30 and the etching mask film 40 . Also, as shown in FIG. 10 , the maximum value of the content ratio of oxygen to silicon is 2.4, which is 3.0 or less, from the interface between the phase shift film 30 and the etching mask film 40 to a depth of 10 nm.

The chromium (Cr) generated by etching the mask film 40 disappears until the peak of oxygen (O) generated by the transparent substrate 20 appears (before the molybdenum (Mo) generated by the phase shift film 30 decreases sharply). In the homogeneous composition area, the content of molybdenum (Mo) is 7 atomic % on average, the content of silicon (Si) is 38 atomic % on average, the content of nitrogen (N) is 46 atomic % on average, and the content of oxygen (O) The rate is 9 atomic % on average. In the phase shift film 30, the change in the content of molybdenum (Mo) is the smallest, which is less than 1 atomic %. Next, the change in the content of silicon (Si) is less than 2 atomic %, and the content of oxygen (O) is less than 2 atomic %. The variation is 3 atomic % or less, and the fluctuation of nitrogen (N) content is 4 atomic % or less.

B. Phase shift mask and manufacturing method thereof Using the phase shift mask substrate manufactured in the above manner, a phase shift mask was manufactured by the same method as in Example 1. The cross section of the obtained phase shift mask was observed with a scanning electron microscope. FIG. 12 is a cross-sectional photograph of the phase shift mask of Example 3. FIG.

As shown in FIG. 12 , the phase shift film pattern formed on the phase shift mask of Example 3 has a nearly vertical cross-sectional shape that can fully exert the phase shift effect. Also, in the phase shift film pattern, no penetration was observed at any of the interface with the etching mask film pattern and the interface with the substrate. Also, it has a phase shift film pattern with a small hem width and a small CD variation. In detail, the cross section of the phase shift film pattern includes the upper surface, the lower surface and the side surface of the phase shift film pattern. In the cross-section of the phase shift film pattern, the angle formed by the part where the upper surface meets the side surface (upper side) and the part where the side surface meets the lower surface (lower side) is 79 degrees. Therefore, an excellent phase shift effect is obtained for exposure light including light in the wavelength range of 300 nm to 500 nm, more specifically, composite light including i-rays, h-rays, and g-rays Phase shift mask. Also, CD variation was good at 0.094 μm. Moreover, in the cross-section of the phase shift film pattern of Example 3, the angle formed by the part (upper side) where the upper surface meets the side surface and the part (lower side) where the side surface meets the lower surface is 79 degrees, exceeding the angle that can be obtained by The lower limit of cross-section control for over-etching is 45 degrees. Therefore, when forming the phase shift film pattern of Example 2, the cross-sectional shape can be further verticalized by performing over-etching. Therefore, it can be said that when the phase shift mask of Example 2 is set on the mask stage of the exposure device and exposed to the resist film transferred on the display device, it can be transferred with high precision up to 2.0 μm of fine patterns.

Comparative example 1. A. Phase Shift Mask Substrate and Manufacturing Method In order to manufacture the phase shift mask base of Comparative Example 1, a synthetic quartz glass substrate having a size of 1214 (1220 mm×1400 mm) was prepared as a transparent substrate in the same manner as in Example 1. By the same method as in Example 1, the synthetic quartz glass substrate was carried into the chamber of an in-line sputtering device. The same sputtering palladium material as in Example 1 was used as the first sputtering palladium, the second sputtering palladium, the third sputtering palladium, and the fourth sputtering palladium. Then, after the phase shift film is formed on the transparent substrate, it is taken out from the chamber, and the surface of the phase shift film is cleaned with pure water. The pure water cleaning conditions were set at a temperature of 30°C and a surface treatment time of 300 seconds. Thereafter, by the same method as in Example 1, an etching mask film was formed. In this way, a phase-shift photomask base with a phase-shift film and an etching mask film formed on a transparent substrate is obtained.

The transmittance and retardation of the obtained phase shift film on the base of the phase shift mask (phase shift film in which the surface of the phase shift film was washed with pure water) were measured with MPM-100 manufactured by Lasertec Co., Ltd. . The transmittance and phase difference of the phase shift film were measured using a substrate (dummy substrate) with a phase shift film 30 formed on the main surface of a synthetic quartz glass substrate that was placed on the same tray. . The transmittance and phase difference of the phase shift film were measured by taking out the substrate (dummy substrate) with the phase shift film from the chamber before forming the etching mask film. As a result, the transmittance was 20.0% (wavelength: 365 nm), and the phase difference was 176 degrees (wavelength: 365 nm). Furthermore, the film thickness of the phase shift film washed with pure water was 198 nm, which was reduced from the film thickness immediately after film formation. Also, for the phase shift film, the change in flatness was measured using UltraFLAT 200M (manufactured by Corning Tropel Co., Ltd.), and the film stress was calculated to be 0.46 GPa. The change in transmittance and phase difference of the phase shift film 30 to the chemical solution (sulfuric acid hydrogen peroxide mixture, ammonia water hydrogen peroxide mixture, ozone water) used for cleaning the phase shift mask is small, It has high chemical resistance and washing resistance.

Moreover, the reflectance and optical density of the film surface were measured with the spectrophotometer SolidSpec-3700 manufactured by Shimadzu Corporation about the obtained phase shift mask base. The film surface reflectance of the phase shift mask substrate (etching mask film) is 8.3% (wavelength: 436 nm), and the optical density OD is 4.0 (wavelength: 436 nm). It can be seen that this etching mask film functions as a light-shielding film whose reflectance on the film surface is low.

Moreover, the composition analysis in the depth direction was performed by X-ray photoelectron spectroscopy (XPS) about the obtained phase shift mask base. FIG. 5 shows the composition analysis results in the depth direction obtained by XPS for the phase shift mask substrate of Comparative Example 1. FIG. FIG. 5 shows the composition analysis results of the etching mask film 40 and the phase shift film 30 on the side of the phase shift film 30 in the phase shift mask substrate. 5 represents the depth (nm) in terms of SiO ₂ of the phase shift mask substrate based on the outermost surface of the etching mask film 40, and the vertical axis represents the content (atomic %). In FIG. 5 , each curve represents changes in the content of silicon (Si), nitrogen (N), oxygen (O), carbon (C), chromium (Cr), and molybdenum (Mo).

As shown in FIG. 5, in the composition analysis results in the depth direction obtained by XPS for the phase shift mask substrate, in the above-mentioned composition gradient region, the ratio of oxygen generated by the phase shift film increases sharply toward the depth direction. , changes at a substantially constant ratio equal to the ratio of oxygen in the above-mentioned uniform composition region. Also, as shown in FIG. 7 , the maximum value of the content ratio of oxygen to silicon was 6.4, and there were regions exceeding 3.0 over the region from the interface between the phase shift film and the etching mask film to a depth of 10 nm. Furthermore, the chromium (Cr) produced by etching the mask film 40 disappears to the uniform composition region of the phase shift film 30 where the peak of oxygen (O) produced by the transparent substrate 20 appears, molybdenum, silicon, nitrogen, oxygen, carbon The content rate is almost the same as in Example 1.

B. Phase shift mask and manufacturing method thereof Using the phase shift mask substrate manufactured in the above manner, a phase shift mask was manufactured by the same method as in Example 1. The cross section of the obtained phase shift mask was observed with a scanning electron microscope. FIG. 6 is a cross-sectional photograph of the phase shift mask of Comparative Example 1. FIG.

As shown in FIG. 6 , the phase shift film pattern formed on the phase shift mask of Comparative Example 1 has a linear tapered shape. In the cross-section of the phase shift film pattern, the angle formed by the part where the upper surface meets the side surface (upper side) and the part where the side surface meets the lower surface (lower side) is 5 degrees. Therefore, the obtained phase shift mask cannot obtain exposure light including light in the wavelength range of 300 nm to 500 nm, more specifically composite light including i-rays, h-rays, and g-rays. Full phase shift effect. Also, the CD deviation was 0.230 μm. Furthermore, in the cross-section of the phase shift film pattern of Comparative Example 1, the angle formed by the part (upper side) where the upper surface meets the side surface and the part (lower side) where the side surface meets the lower surface is 5 degrees, which is not reachable. The lower limit of cross section control is 45 degrees by overetching. Therefore, when forming the phase shift film pattern of Comparative Example 1, it cannot be expected to further verticalize the cross-sectional shape by performing overetching. Therefore, it can be predicted that when the phase shift mask of Comparative Example 1 is set on the mask stage of the exposure device and exposed to the resist film transferred on the display device, it is not possible to transfer the micron film less than 2.0 μm. pattern.

Also, as shown in FIG. 7 , the content ratio of oxygen to silicon exceeded 3.0 throughout the region from the interface between the phase shift film 30 and the etching mask film 40 to a depth of 10 nm. Considering these aspects, and the fact that the composition of Example 1 and Comparative Example 1 in the uniform composition region is substantially the same, it can be said that throughout the interface between the phase shift film and the etching mask film to a depth of 10 nm, oxygen relative to silicon The content ratio of 3.0 or less is an important factor for obtaining a phase shift mask base with a high transmittance, which can pattern the phase shift film into a cross-sectional shape that can fully exert the phase shift effect.

Furthermore, in the above-mentioned embodiments, the case of using molybdenum as the transition metal has been described, and the same effects as above can be obtained when other transition metals are used. In addition, in the above-mentioned embodiment, the phase shift mask base for display device manufacture and the example of the phase shift mask for display device manufacture were demonstrated, but it is not limited to this. The phase-shift mask substrate and the phase-shift mask of the present invention can also be applied to semiconductor device manufacturing, MEMS (Micro Electro Mechanical System, micro-electromechanical system) manufacturing, printed substrates, and the like. In addition, in the above-mentioned embodiments, an example in which the size of the transparent substrate is 8092 size (800 mm×920 mm×10 mm) has been described, but it is not limited thereto. In the case of a phase-shift mask substrate for display device manufacturing, a large-size transparent substrate is used, and the size of the transparent substrate is 300 mm or more in length on one side. The size of the transparent substrate used in the phase shift mask base for display device manufacturing is, for example, 330 mm×450 mm or more and 2280 mm×3130 mm or less. In addition, in the case of semiconductor device manufacturing, MEMS manufacturing, and printed substrate phase-shift mask substrates, small-size transparent substrates are used, and the size of the transparent substrate is 9 inches or less in length on one side. The size of the transparent substrate used in the phase shift mask base for the above-mentioned application is, for example, 63.1 mm×63.1 mm or more and 228.6 mm×228.6 mm or less. Generally, semiconductor manufacturing and MEMS manufacturing use 6025 size (152 mm×152 mm) or 5009 size (126.6 mm×126.6 mm), and printed substrates use 7012 size (177.4 mm×177.4 mm) or 9012 size (228.6 mm ×228.6 mm).

10‧‧‧Phase shift mask substrate 20‧‧‧Transparent substrate 30‧‧‧phase shift film 30a‧‧‧Phase shift film pattern 40‧‧‧Etching mask film 40a‧‧‧First etching mask pattern 40b‧‧‧Second etching mask pattern 50‧‧‧1st resist film pattern 60‧‧‧The second resist film pattern 100‧‧‧phase shift mask

FIG. 1 is a schematic diagram showing the film composition of a phase shift mask substrate. 2( a ) to ( e ) are schematic diagrams showing the manufacturing steps of the phase shift mask. FIG. 3 is a graph showing the composition analysis results in the depth direction of the phase shift mask substrate of Example 1. FIG. FIG. 4 is a cross-sectional photograph of the phase shift mask of Embodiment 1. FIG. FIG. 5 is a graph showing the composition analysis results in the depth direction of the phase shift mask substrate of Comparative Example 1. FIG. FIG. 6 is a cross-sectional photograph of the phase shift mask of Comparative Example 1. FIG. Fig. 7 shows the O/Si ratio (oxygen relative to Si content ratio) diagram. FIG. 8 is a graph showing the composition analysis results in the depth direction of the phase shift mask substrate of Example 2. FIG. FIG. 9 is a cross-sectional photograph of the phase shift mask of Example 2. FIG. 10 is a graph showing the O/Si ratio (the content ratio of oxygen to silicon) in the depth direction obtained by XPS for the phase shift mask substrates of Examples 2 and 3. FIG. FIG. 11 is a graph showing the composition analysis results in the depth direction of the phase shift mask substrate of Example 3. FIG. FIG. 12 is a cross-sectional photograph of the phase shift mask of Example 3. FIG.

Claims (11)

A phase-shift mask base, characterized in that: it has a phase-shift film on a transparent substrate, and has an etching mask film on the phase-shift film, and the above-mentioned phase-shift mask base is a master , the master plate is used to form a phase shift film on the above-mentioned transparent substrate by wet-etching the above-mentioned phase shift film by using an etch-mask film pattern having a desired pattern formed on the above-mentioned etch-mask film as a mask. A phase shift mask of a shift film pattern, wherein the phase shift film contains a transition metal, silicon, and oxygen, and the content of oxygen is not less than 5 atomic % and not more than 70 atomic %. A composition gradient region is formed at the interface of the mask film, and the composition gradient region includes a region where the oxygen content increases stepwise and/or continuously toward the depth direction, throughout the phase shift film and the etching mask film From the interface to the region with a depth of 10nm, the content ratio of oxygen to silicon is 3.0 or less. The phase shift mask substrate according to claim 1, wherein the phase shift film includes multiple layers. The phase shift mask substrate according to claim 1, wherein the phase shift film comprises a single layer. The phase shift mask substrate according to any one of claims 1 to 3, wherein the phase shift film contains nitrogen. The phase shift mask substrate as claimed in claim 4, wherein the content of nitrogen in the above phase shift film is 2 Atomic % or more and 60 atomic % or less. The phase shift mask substrate according to any one of claims 1 to 3, wherein the film stress of the phase shift film is not less than 0.2 GPa and not more than 0.8 GPa. The phase-shift photomask substrate according to any one of claims 1 to 3, wherein the above-mentioned etching mask film comprises a chrome-based material. The phase-shift photomask substrate according to any one of claims 1 to 3, wherein the above-mentioned etching mask film contains at least any one of nitrogen, oxygen, and carbon. The phase-shift photomask substrate according to any one of claims 1 to 3, wherein the above-mentioned transparent substrate is a rectangular substrate, and the length of the short side of the transparent substrate is more than 300 mm. A method for manufacturing a phase-shift mask, characterized in that it comprises the following steps: preparing a phase-shift mask substrate according to any one of claims 1 to 9; forming a resist film on the above-mentioned phase-shift mask substrate forming a resist film pattern by drawing a desired pattern on the above resist film and developing it, using the resist film pattern as a mask, and patterning the above etching mask film by wet etching, forming the etching mask pattern; and forming the phase shift film pattern on the transparent substrate by wet etching the phase shift film by using the etching mask pattern as a mask. A method of manufacturing a display device, characterized in that it has the following steps: using a phase-shifted mask manufactured using a phase-shifted mask substrate according to any one of claims 1 to 9, or using a Manufacturing method of phase shift mask The manufactured phase shift mask exposes and transfers the transfer pattern to the resist film on the display device.

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